New Technology

Swiss adventurer Bertrand Picard is set to unveil a prototype of the solar-powered plane he hopes eventually to fly around the world.

The initial version, spanning 61m but weighing just 1,500kg, will undergo trials to prove it can fly at night.

Mr Picard, who made history by circling the globe non-stop in a balloon in 1999, says he wants to demonstrate the potential of renewable energies.

He expects to make a crossing of the Atlantic in 2012.

The flight would be a risky endeavour. Only now is solar and battery technology becoming mature enough to sustain flight through the night - and then only in unmanned planes.

But Picard's Solar Impulse team has invested tremendous energy - and no little money - in trying to find what they believe is a breakthrough design.

"I love this type of vision where you set the goal and then you try to find a way to reach it, because this is challenging," he told BBC News.

Testing programme

The HB-SIA has the look of a glider but is on the scale - in terms of its width - of a modern airliner.

The aeroplane incorporates composite materials to keep it extremely light and uses super-efficient solar cells, batteries, motors and propellers to get it through the dark hours.


Picard will begin testing with short runway flights in which the plane lifts just a few metres into the air.

As confidence in the machine develops, the team will move to a day-night circle. This has never been done before in a piloted solar-powered plane.

HB-SIA should be succeeded by HB-SIB. It is likely to be bigger, and will incorporate a pressurised capsule and better avionics.

It is probable that Picard will follow a route around the world in this aeroplane similar to the path he took in the record-breaking Breitling Orbiter 3 balloon - travelling at a low latitude in the Northern Hemisphere. The flight could go from the United Arab Emirates, to China, to Hawaii, across the southern US, southern Europe, and back to the UAE.

Measuring success

Although the vehicle is expected to be capable of flying non-stop around the globe, Picard will in fact make five long hops, sharing flying duties with project partner Andre Borschberg.

"The aeroplane could do it theoretically non-stop - but not the pilot," said Picard.

"We should fly at roughly 25 knots and that would make it between 20 and 25 days to go around the world, which is too much for a pilot who has to steer the plane.

"In a balloon you can sleep, because it stays in the air even if you sleep. We believe the maximum for one pilot is five days."

The public unveiling on Friday of the HB-SIA is taking place at Dubendorf airfield near Zürich.

"The real success for Solar Impulse would be to have enough millions of people following the project, being enthusiastic about it, and saying 'if they managed to do it around the world with renewable energies and energy savings, then we should be able to do it in our daily life'."

Applied scientists at Harvard University in collaboration with researchers from the German universities of Jena, Gottingen, and Bremen, have developed a new technique for fabricating nanowire photonic and electronic integrated circuits that may one day be suitable for high-volume commercial production.
Spearheaded by graduate student Mariano Zimmler and Federico Capasso, Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering, both of Harvard's School of Engineering and Applied Sciences (SEAS), and Prof. Carsten Ronning of the University of Jena, the findings will be published in Nano Letters. The researchers have filed for U.S. patents covering their invention.

While semiconductor nanowires---rods with an approximate diameter of one-thousandth the width of a human hair---can be easily synthesized in large quantities using inexpensive chemical methods, reliable and controlled strategies for assembling them into functional circuits have posed a major challenge. By incorporating spin-on glass technology, used in silicon integrated circuits manufacturing, and photolithography, transferring a circuit pattern onto a substrate with light, the team demonstrated a reproducible, high-volume, and low-cost fabrication method for integrating nanowire devices directly onto silicon.

"Because our fabrication technique is independent of the geometrical arrangement of the nanowires on the substrate, we envision further combining the process with one of the several methods already developed for the controlled placement and alignment of nanowires over large areas," said Capasso. "We believe the marriage of these processes will soon provide the necessary control to enable integrated nanowire photonic circuits in a standard manufacturing setting."

The structure of the team's nanowire devices is based on a sandwich geometry: a nanowire is placed between the highly conductive substrate, which functions as a common bottom contact, and a top metallic contact, using spin-on glass as a spacer layer to prevent the metal contact from shorting to the substrate. As a result current can be uniformly injected along the length of the nanowires. These devices can then function as light-emitting diodes, with the color of light determined by the type of semiconductor nanowire used.

To demonstrate the potential scalability of their technique, the team fabricated hundreds of nanoscale ultraviolet light-emitting diodes by using zinc oxide nanowires on a silicon wafer. More broadly, because nanowires can be made of materials commonly used in electronics and photonics, they hold great promise for integrating efficient light emitters, from ultraviolet to infrared, with silicon technology. The team plans to further refine their novel method with an aim towards electrically contacting nanowires over entire wafers.

"Such an advance could lead to the development of a completely new class of integrated circuits, such as large arrays of ultra-small nanoscale lasers that could be designed as high-density optical interconnects or be used for on-chip chemical sensing," said Ronning.

The team's co-authors are postdoctoral fellow Wei Yi and Venkatesh Narayanamurti, John A. and Elizabeth S. Armstrong Professor and dean, both of Harvard's School of Engineering and Applied Sciences; graduate student Daniel Stichtenoth, University of Gottingen; and postdoctoral fellow Tobias Voss, University of Bremen.

The research was supported by the National Science Foundation (NSF) and the German Research Foundation. The authors also acknowledge the support of two Harvard-based centers, the National Science Foundation Nanoscale Science and Engineering Center (NSEC) and the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Infrastructure Network (NNIN).


http://www.fas.harvard.edu/home/

Chemists and engineers at Harvard University have made robust circuits from minuscule nanowires that align themselves on a chip of glass during low-temperature fabrication, creating rudimentary electronic devices that offer solid performance without high-temperature production or high-priced silicon.

The researchers, led by chemist Charles M. Lieber and engineer Donhee Ham, produced circuits at low temperature by running a nanowire-laced solution over a glass substrate, followed by regular photolithography to etch the pattern of a circuit. Their merging of low-temperature fabrication and nanowires in a high-performance electronic device is described this week in the journal Nature.

"By using common, lightweight and low-cost materials such as glass or even plastic as substrates, these nanowire circuits could make computing devices ubiquitous, allowing powerful electronics to permeate all aspects of living," says Lieber, the Mark Hyman Jr. Professor of Chemistry in Harvard's Faculty of Arts and Sciences. "Because this technique can create a high-quality circuit at low temperatures, it could be a technology that finally decouples quality electronics from single crystal silicon wafers, which are resilient during high-temperature fabrication but also very expensive."

Lieber, Ham and colleagues used their technique to produce nanowire-based logical inverters and ring oscillators, which are inverters in series. The ring oscillator devices, which are critical for virtually all digital electronics, performed considerably better than comparable ring oscillators produced at low temperatures using organic semiconductors, achieving a speed roughly 20 times faster. The nanowire-derived ring oscillators reached a speed of 11.7 megahertz, outpacing by a factor of roughly 10,000 the excruciatingly slow performance attained by other nanomaterial circuits.

"These nanowire circuits' performance was impressive," says Ham, assistant professor of electrical engineering in Harvard's Division of Engineering and Applied Sciences. "This finding gives us confidence that we can ramp up these elementary circuits to build more complex devices, which is something we now plan to do."

Lieber and Ham say these functional nanowire circuits demonstrate nanomaterials' potential in electronics applications. The circuits could be used in devices such as low-cost radio-frequency tags and fully integrated high-refresh-rate displays, the scientists write in Nature; on a larger scale, such circuits could provide a foundation for more complex nanoelectronics. The technique Lieber and Ham used to produce a nanowire-based circuit on a glass substrate is also compatible with other commonplace materials such as plastics, broadening its potential applicability.


http://www.harvard.edu/

MIT and Boston University engineers have designed cells that can count and "remember" cellular events, using simple circuits in which a series of genes are activated in a specific order.
Such circuits, which mimic those found on computer chips, could be used to count the number of times a cell divides, or to study a sequence of developmental stages. They could also serve as biosensors that count exposures to different toxins.

The team developed two types of cellular counters, both described in the May 29 issue of Science. Though the cellular circuits resemble computer circuits, the researchers are not trying to create tiny living computers.

"I don't think computational circuits in biology will ever match what we can do with a computer," said Timothy Lu, a graduate student in the Harvard-MIT Division of Health Sciences and Technology (HST) and one of two lead authors of the paper.

Performing very elaborate computing inside cells would be extremely difficult because living cells are much harder to control than silicon chips. Instead, the researchers are focusing on designing small circuit components to accomplish specific tasks.

"Our goal is to build simple design tools that perform some aspect of cellular function," said Lu.

Ari Friedland, a graduate student at Boston University, is also a lead author of the Science paper. Other authors are Xiao Wang, postdoctoral associate at BU; David Shi, BU undergraduate; George Church, faculty member at Harvard Medical School and HST; and James Collins, professor of biomedical engineering at BU.

Learning to count

To demonstrate their concept, the team built circuits that count up to three cellular events, but in theory, the counters could go much higher.

The first counter, dubbed the RTC (Riboregulated Transcriptional Cascade) Counter, consists of a series of genes, each of which produces a protein that activates the next gene in the sequence.

With the first stimulus — for example, an influx of sugar into the cell — the cell produces the first protein in the sequence, an RNA polymerase (an enzyme that controls transcription of another gene). During the second influx, the first RNA polymerase initiates production of the second protein, a different RNA polymerase.

The number of steps in the sequence is, in theory, limited only by the number of distinct bacterial RNA polymerases. "Our goal is to use a library of these genes to create larger and larger cascades," said Lu.

The counter's timescale is minutes or hours, making it suitable for keeping track of cell divisions. Such a counter would be potentially useful in studies of aging.

The RTC Counter can be "reset" to start counting the same series over again, but it has no way to "remember" what it has counted. The team's second counter, called the DIC (DNA Invertase Cascade) Counter, can encode digital memory, storing a series of "bits" of information.

The process relies on an enzyme known as invertase, which chops out a specific section of double-stranded DNA, flips it over and re-inserts it, altering the sequence in a predictable way.

The DIC Counter consists of a series of DNA sequences. Each sequence includes a gene for a different invertase enzyme. When the first activation occurs, the first invertase gene is transcribed and assembled. It then binds the DNA and flips it over, ending its own transcription and setting up the gene for the second invertase to be transcribed next.

When the second stimulus is received, the cycle repeats: The second invertase is produced, then flips the DNA, setting up the third invertase gene for transcription. The output of the system can be determined when an output gene, such as the gene for green fluorescent protein, is inserted into the cascade and is produced after a certain number of inputs or by sequencing the cell's DNA.

This circuit could in theory go up to 100 steps (the number of different invertases that have been identified). Because it tracks a specific sequence of stimuli, such a counter could be useful for studying the unfolding of events that occur during embryonic development, said Lu.

Other potential applications include programming cells to act as environmental sensors for pollutants such as arsenic. Engineers would also be able to specify the length of time an input needs to be present to be counted, and the length of time that can fall between two inputs so they are counted as two events instead of one.

They could also design the cells to die after a certain number of cell divisions or night-day cycles.

"There's a lot of concern about engineered organisms — if you put them in the environment, what will happen?" said Collins, who is also a Howard Hughes Medical Institute investigator. These counters "could serve as a programmed expiration date for engineered organisms."

The research was funded by the National Institute of Health Director's Pioneer Award Program, the National Science Foundation FIBR program, and the Howard Hughes Medical Institute.


http://web.mit.edu/

Most chemical elements become superconducting at low temperatures or high pressures, but until now, copper, silver, gold, and the semiconductor germanium, for example, have all refused superconductivity. Scientists at the Forschungszentrum Dresden-Rossendorf (FZD) research center were now able to produce superconducting germanium for the first time. Furthermore, they could unravel a few of the mysteries which come along with superconducting semiconductors.
Superconductors are substances that conduct electricity without losses when cooled down to very low temperatures. Pure semiconductors, like silicon or germanium, are almost non-conducting at low temperatures, but transform into conducting materials after doping with foreign atoms. An established method of doping is ion implantation (ions = charged atoms) by which foreign ions are embedded into the crystal lattice of a semiconductor. To produce a superconducting semiconductor, an extreme amount of foreign atoms are necessary, even more than the substance would usually be able to absorb. At the FZD, germanium samples were doped with about six gallium atoms per 100 germanium atoms. With these experiments, the scientists could prove indeed that the doped germanium layer of only sixty nanometers thickness became superconducting, and not just the clusters of foreign atoms which could easily form during extreme doping .

As the germanium lattice is heavily damaged by ion implantation, it has to be repaired afterwards. For such purposes, a flash-lamp annealing facility has been developed at the FZD. Its application allows for a repair of the destroyed crystal lattice by rapidly heating the sample surface (within few milliseconds) while the distribution of the dopant atoms is kept almost the same.

From a scientific point of view, the new material is very promising. It exhibits a surprisingly high critical magnetic field with respect to the temperature where the substance becomes superconducting. For many materials, superconductivity occurs only at very low temperatures, slightly above the absolute zero point of -273 degrees Celsius or 0 Kelvin. The gallium doped germanium samples become superconducting at about 0.5 Kelvin; however, the FZD researchers expect the temperature to increase further by changing various parameters during ion implantation or annealing.

Physicists have been dreaming about superconducting semiconductors for a long time, but saw only few chances for the semiconductor germanium to become superconducting at all. Germanium used to be the material for the first generation of transistors; however, it was soon replaced by silicon, the current material for microelectronics. Recently, the “old” semiconductor material germanium has aroused more and more interest, as it allows, compared to silicon, for more rapid circuits.

Experts even believe germanium to be rediscovered for micro- and nanoelectronics. The reason for such a renaissance lies in the fact that miniaturization in microelectronics industry using silicon is coming to an end. Today, extremely thin oxide layers are needed for transistors, down to a level where silicon oxide does not work well any more. Germanium as a new material for chips would come along with two big advantages: it would enable both faster processes and further miniaturization in micro- and nanoelectronics. Superconducting germanium could thus help to realize circuits for novel computers.

The scientists at the Forschungszentrum Dresden-Rossendorf followed a targeted approach when searching for a new superconducting semiconductor. Instead of doping with boron, which had resulted in superconducting silicon two years ago in France, the scientists choose gallium because of its higher solubility in germanium. In many systematic experiments they proved that the superconductivity of germanium can be reproduced. Furthermore, they were able to show that the transition temperature marking the start of superconductivity can be raised within certain limits.

In the future, the scientists at the two FZD institutes “Ion Beam Physics and Materials Research” and “Dresden High Magnetic Field Laboratory” will combine their know-how in order to fine-tune different rather complex parameters for further experiments, thus hopefully discovering further mysteries of superconducting semiconductors.

MicroOLED, a developer of efficient organic light emitting diode technologies (OLED),has announced the release of a new high-definition multimedia interface allowing its high-resolution microdisplays to connect to the Texas Instruments Incorporated (TI) OMAP™ platform.

A groundbreaking innovation for mobile gaming and video entertainment, the new interface enables 3D video or 3D gaming while using specially-designed video glasses. Leveraging a single HDMI connection to the mobile phone, the solution generates both left and right SD video streams onto the microdisplays embedded within the glasses, thus allowing gamers and video enthusiasts to view and/or interact with their favorite multimedia content while on the go.

The new system also features the MicroOLED wide video graphics array plus (WVGA+) high-resolution OLED microdisplay withRGB video interface. This microdisplay is based on MicroOLED’s proprietary OLED-on-CMOS (Complementary Metal-Oxide-Semiconductor) technology, which delivers high-resolution video while offering an extremely small footprint, low power consumption and outstanding image picture quality. This advancement makes the technology ideally suited for high-end video glasses that support best in class 3D image quality and mobile entertainment, whether at home or on the move.

MicroOLED’s technology successfully connects to TI’s proven OMAP platform via a single HDMI connection, delivering optimal processing performance to decode high definition video streams along with power from which MicroOLED’s technology generates two 873 x 500 pixels videos. This dual-technology combination will empower mobile telecommunications carriers to sell full, DVD-quality 3D content on their video-on-demand portals for mobile applications. The result of this effort is the creation of technologies for 3D mobile devices and applications enabling life-like user experience.

“By integrating our energy-efficient microdisplay into 3D video glasses and this 3D interface, we are enabling a full range of new mobile entertainment applications ranging from 3D gaming to HD mobile video. This is made possible only by combining TI’s OMAP platform and MicroOLED’s microdisplays, two leading technologies that deliver low power consumption and high performance,” explained Eric Marcellin-Dibon, CEO of MICROOLED.


http://www.cea.fr/

With much of the mobile world yet to migrate to 3G mobile communications, let alone 4G, European researchers are already working on a new technology able to deliver data wirelessly up to 12.5Gb/s.

The technology – known as ‘millimetre (mm)-wave’ or microwave photonics – has commercial applications not just in telecommunications (access and in-house networks) but also in instrumentation, radar, security, radio astronomy and other fields.

Despite the quantum leap in performance made possible by combining the latest radio and optics technologies to produce mm-wave components, it will probably only be a few years before there are real benefits for the average EU citizen.

This is thanks to research and development work being done by the EU-funded project IPHOBAC, which brings together partners from both academia and industry with the aim of developing a new class of components and systems for mm-wave applications.

The mm-wave band is the extremely high frequency part of the radio spectrum, from 30 to 300 gigahertz (GHz), and it gets it name from having a wavelength of one to 10mm. Until now, the band has been largely undeveloped, so the new technology makes available for exploitation more of the scarce and much-in-demand spectrum.

New products from Europe

IPHOBAC is not simply a ‘paper project’ where the technology is researched, but very much a practical exercise to develop and commercialise a new class of products with a ‘made in Europe’ label on them.

While several companies in Japan and the USA have been working on merging optical and radio frequency technologies, IPHOBAC is the world’s first fully integrated effort in the field, with a lot of different companies involved. This has resulted in the three-year project, which runs until end-2009, already having an impressive list of achievements to its name.

It recently unveiled a tiny component, a transmitter able to transmit a continuous signal not only through the entire mm-wave band but beyond. Its full range is 30 to 325GHz and even higher frequency operation is now under investigation. The first component worldwide able to deliver that range of performance, it will be used in both communications and radar systems. Other components developed by the project include 110GHz modulators, 110GHz photodetectors, 300GHz dual-mode lasers, 60GHz mode-locked lasers, and 60GHz transceivers.

Truly disruptive technology

Project coordinator Andreas Stöhr says millimetre-wave photonics is a truly disruptive technology for high frequency applications. “It offers unique capabilities such as ultra-wide tunability and low-phase noise which are not possible with competing technologies, such as electronics,” he says.

What this will mean in practical terms is not only ultra-fast wireless data transfer over telecommunications networks, but also a whole range of new applications (http://www.iphobac-survey.org).

One of these, a 60GHz Photonic Wireless System, was demonstrated at the ICT 2008 exhibition in Lyon and was voted into the Top Ten Best exhibits. The system allows wireless connectivity in full high definition (HD) between devices in the home, such as a set-top box, TV, PC, and mobile devices. It is the first home area network to demonstrate the speeds necessary for full wireless HD of up to 3Gb/s.

The system can also be used to provide multi-camera coverage of live events in HD. “There is no time to compress the signal as the director needs to see live feed from every camera to decide which picture to use, and ours is the only technology which can deliver fast enough data rates to transmit uncompressed HD video/audio signals,” says Stöhr.

The same technology has been demonstrated for access telecom networks and has delivered world record data rates of up to 12.5Gb/s over short- to medium-range wireless spans, or 1500 times the speed of upcoming 4G mobile networks.

One way in which the technology can be deployed in the relatively short term, according to Stöhr, is wirelessly supporting very fast broadband to remote areas. “You can have your fibre in the ground delivering 10Gb/s but we can deliver this by air to remote areas where there is no fibre or to bridge gaps in fibre networks,” he says.

Systems for outer space

The project is also developing systems for space applications, working with the European Space Agency. Stöhr said he could not reveal details as this has not yet been made public, save to say the systems will operate in the 100GHz band and are needed immediately.

There are various ongoing co-operation projects with industry to commercialise the components and systems, and some components are already at a pre-commercial stage and are being sold in limited numbers. There are also ongoing talks with some of the biggest names in telecommunications, including Siemens, Ericsson, Thales Communications and Malaysia Telecom.

“In just a few years time everybody will be able to see the results of the IPHOBAC project in telecommunications, in the home, in radio astronomy and in space. It is a completely new technology which will be used in many applications even medical ones where mm-wave devices to detect skin cancer are under investigation,” says Stöhr.


http://cordis.europa.eu./ictresults/

The Mathematical Institute of the University of Cologne conducts research within in the European project ICESTARS (Integrated Circuit/Electromagnetic Simulation and design Technologies for Advanced Radio Systems-on-chip). New mathematical algorithms for the next radio chip generation will be developed under the leadership of Prof. Dr. Caren Tischendorf.
According to Prof. Tischendorf: "In the future, mobile devices will provide customers with services ranging from telephony and internet to mobile TV and remote banking, anytime, anywhere. It is impossible to realize the necessary, extremely high data transfer rates within the frequency bands used today (approximately 1-3GHz)." The project serves to enable the development of low-cost wireless chips that can operate in a frequency range of up to 100GHz.

The leader of the ICESTARS project, Marq Kole of NXP Semiconductors says: "By the end of the project in 2010 we aim to have accelerated the chip development process in the extremely high frequency range by new methods and simulation tools in order to actively maintain the European chip developers on a top position over the whole spectrum of wireless communications." The ICESTARS project is funded by the European Commission within the EU 7th framework program and lead by Dutch company NXP Semiconductors. The German semiconductor company Qimonda will develop advanced analog simulation techniques in the framework of this project.

Additional partners are the software developing companies AWR-APLAC from Finland with a focus onto frequency-domain simulation algorithms and MAGWEL from Belgium with a focus onto electromagnetic simulations. Besides the University of Cologne, the university partners Upper Austria University of Applied Sciences, the University of Wuppertal from Germany and the University of Oulu from Finland are concentrating on modeling questions, algorithmic problems and simulation issues to be solved for a robust and accelerated automated testing of analog circuits with digital signal processing in the extremely high frequency range.


http://www.uni-koeln.de/

MIT engineers have built a fast, ultra-broadband, low-power radio chip, modeled on the human inner ear, that could enable wireless devices capable of receiving cell phone, Internet, radio and television signals.
Rahul Sarpeshkar, associate professor of electrical engineering and computer science, and his graduate student, Soumyajit Mandal, designed the chip to mimic the inner ear, or cochlea. The chip is faster than any human-designed radio-frequency spectrum analyzer and also operates at much lower power.

"The cochlea quickly gets the big picture of what's going on in the sound spectrum," said Sarpeshkar. "The more I started to look at the ear, the more I realized it's like a super radio with 3,500 parallel channels."

Sarpeshkar and his students describe their new chip, which they have dubbed the "radio frequency (RF) cochlea," in a paper to be published in the June issue of the IEEE Journal of Solid-State Circuits. They have also filed for a patent to incorporate the RF cochlea in a universal or software radio architecture that is designed to efficiently process a broad spectrum of signals including cellular phone, wireless Internet, FM, and other signals.

The RF cochlea mimics the structure and function of the biological cochlea, which uses fluid mechanics, piezoelectrics and neural signal processing to convert sound waves into electrical signals that are sent to the brain.

As sound waves enter the cochlea, they create mechanical waves in the cochlear membrane and the fluid of the inner ear, activating hair cells (cells that cause electrical signals to be sent to the brain). The cochlea can perceive a 100-fold range of frequencies -- in humans, from 100 to 10,000 Hz. Sarpeshkar used the same design principles in the RF cochlea to create a device that can perceive signals at million-fold higher frequencies, which includes radio signals for most commercial wireless applications.

The device demonstrates what can happen when researchers take inspiration from fields outside their own, says Sarpeshkar.

"Somebody who works in radio would never think of this, and somebody who works in hearing would never think of it, but when you put the two together, each one provides insight into the other," he says. For example, in addition to its use for radio applications, the work provides an analysis of why cochlear spectrum analysis is faster than any known spectrum-analysis algorithm. Thus, it sheds light on the mechanism of hearing as well.

The RF cochlea, embedded on a silicon chip measuring 1.5 mm by 3 mm, works as an analog spectrum analyzer, detecting the composition of any electromagnetic waves within its perception range. Electromagnetic waves travel through electronic inductors and capacitors (analogous to the biological cochlea's fluid and membrane). Electronic transistors play the role of the cochlea's hair cells.

The analog RF cochlea chip is faster than any other RF spectrum analyzer and consumes about 100 times less power than what would be required for direct digitization of the entire bandwidth. That makes it desirable as a component of a universal or "cognitive" radio, which could receive a broad range of frequencies and select which ones to attend to.

Biological inspiration

This is not the first time Sarpeshkar has drawn on biology for inspiration in designing electronic devices. Trained as an engineer but also a student of biology, he has found many similar patterns in the natural and man-made worlds. For example, Sarpeshkar's group, in MIT's Research Laboratory of Electronics, has also developed an analog speech-synthesis chip inspired by the human vocal tract and a novel analysis-by-synthesis technique based on the vocal tract. The chip's potential for robust speech recognition in noise and its potential for voice identification have several applications in portable devices and security applications.

The researchers have built circuits that can analyze heart rhythms for wireless heart monitoring, and are also working on projects inspired by signal processing in cells. In the past, his group has worked on hybrid analog-digital signal processors inspired by neurons in the brain.

Sarpeshkar says that engineers can learn a great deal from studying biological systems that have evolved over hundreds of millions of years to perform sensory and motor tasks very efficiently in noisy environments while using very little power.

"Humans have a long way to go before their architectures will successfully compete with those in nature, especially in situations where ultra-energy-efficient or ultra-low-power operation are paramount," he said. Nevertheless, "We can mine the intellectual resources of nature to create devices useful to humans, just as we have mined her physical resources in the past.


http://www.mit.edu/